RTF_CREATE_FIR_LOWPASS(3)					 rtfilter library					 RTF_CREATE_FIR_LOWPASS(3)

NAME

       rtf_create_fir_lowpass, rtf_create_fir_highpass, rtf_create_fir_bandpass - Creates FIR lowpass, highpass and bandpass windowed sinc filters

SYNOPSIS

       #include <rtf_common.h>

       hfilter rtf_create_fir_lowpass(unsigned int nch, int proctype,
				      double fc, unsigned int hlen,
				      KernelWindow wndtype);
       hfilter rtf_create_fir_highpass(unsigned int nch, int proctype,
				      double fc, unsigned int hlen,
				      KernelWindow wndtype);
       hfilter rtf_create_fir_bandpass(unsigned int nchann, int proctype,
				       double fc_low, double fc_high,
				       unsigned int hlen,
				       KernelWindow wndtype);

DESCRIPTION

       rtf_create_fir_lowpass()  creates  a  lowpass windowed sinc filter processing nchann channels of data type specified by proctype with fc as
       normalized cutoff frequency and hlen as the half length of the window.

       rtf_create_fir_highpass() is the same as rtf_create_fir_lowpass() but creates a highpass filter.

       rtf_create_fir_bandpass() is the same but creates a bandpass filter with fc_low and fc_high as respectively the lowpass and  highpass  nor-
       malized cutoff frequencies.

       A  normalized  frequency is the ratio between the absolute frequency and the sampling frequency (i.e. a value of 1.0 refers to the sampling
       frequency).

       The parameter proctype has the same meaning as in rtf_create_filter(3). Refers to its manpage for more details.

       The parameter wndtype specifies the type of window applied to the impulse response and can take the following values: BLACKMAN_WINDOW, HAM-
       MING_WINDOW or RECT_WINDOW (see a book on signal processing for details about their meaning).

RETURN VALUE

       Returns the handle to the created filter in case of success, NULL otherwise.

SEE ALSO

       rtf_create_filter(3), rtf_destroy_filter(3)

EPFL
								       2010						 RTF_CREATE_FIR_LOWPASS(3)